This invention relates to a filter device for filtering liquids or gases comprising a housing that can be opened and a filter element disposed in the housing.
Published U.S. patent application Ser. No. US 2002/0170279 describes a filter unit which has a filter element situated in a housing. The connection between the housing and the filter element is accomplished via defined gear teeth and/or a geometric embodiment of the end disk of the filter element. One disadvantage of the known device is that a defined correlation of certain element contours to the housing is impossible. Therefore, an element not having the required contour can easily be installed in the housing. Consequently, incorrect parts can be installed in the existing housing. Likewise, parts that fail to meet requirements with regard to filtration properties can also be installed.
Published German patent application no. DE 44 02 836, for example, describes an arrangement in which the correct use of suitable replacement parts is ensured by the fact that the respective part for attachment can be attached to the unit only according to a lock-and-key principle. However, there is still the problem here that careless use of replacement parts could result in a shortened lifetime or impaired functioning of the units. Furthermore, improper use or consequences thereof are difficult or impossible to detect and correction of a mistake is relatively difficult.
Furthermore, published international patent application no. WO 01/52185 discloses a method of monitoring high-maintenance replacement parts on a unit, in which a memory module in the form of a transponder, for example, is arranged on a filter element to transmit the correct use and to transmit the filter properties at the same time. However, this method requires an additional analyzer unit to display the data.